7 files changed, 110 insertions, 3 deletions

diff --git a/crates/ra_ide_api/src/goto_type_definition.rs b/crates/ra_ide_api/src/goto_type_definition.rs
new file mode 100644
index 000000000..de2b9d3c3
--- /dev/null
+++ b/crates/ra_ide_api/src/goto_type_definition.rs
@@ -0,0 +1,66 @@
+use ra_db::SourceDatabase;
+use ra_syntax::{
+    AstNode, ast,
+    algo::find_token_at_offset
+};
+
+use crate::{FilePosition, NavigationTarget, db::RootDatabase, RangeInfo};
+
+pub(crate) fn goto_type_definition(
+    db: &RootDatabase,
+    position: FilePosition,
+) -> Option<RangeInfo<Vec<NavigationTarget>>> {
+    let file = db.parse(position.file_id);
+
+    let node = find_token_at_offset(file.syntax(), position.offset).find_map(|token| {
+        token
+            .parent()
+            .ancestors()
+            .find(|n| ast::Expr::cast(*n).is_some() || ast::Pat::cast(*n).is_some())
+    })?;
+
+    let analyzer = hir::SourceAnalyzer::new(db, position.file_id, node, None);
+
+    let ty: hir::Ty = if let Some(ty) = ast::Expr::cast(node).and_then(|e| analyzer.type_of(db, e))
+    {
+        ty
+    } else if let Some(ty) = ast::Pat::cast(node).and_then(|p| analyzer.type_of_pat(db, p)) {
+        ty
+    } else {
+        return None;
+    };
+
+    let (adt_def, _) = ty.as_adt()?;
+    let nav = NavigationTarget::from_adt_def(db, adt_def);
+
+    Some(RangeInfo::new(node.range(), vec![nav]))
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::mock_analysis::analysis_and_position;
+
+    fn check_goto(fixture: &str, expected: &str) {
+        let (analysis, pos) = analysis_and_position(fixture);
+
+        let mut navs = analysis.goto_type_definition(pos).unwrap().unwrap().info;
+        assert_eq!(navs.len(), 1);
+        let nav = navs.pop().unwrap();
+        nav.assert_match(expected);
+    }
+
+    #[test]
+    fn goto_type_definition_works_simple() {
+        check_goto(
+            "
+            //- /lib.rs
+            struct Foo;
+            fn foo() {
+                let f: Foo;
+                f<|>
+            }
+            ",
+            "Foo STRUCT_DEF FileId(1) [0; 11) [7; 10)",
+        );
+    }
+}
diff --git a/crates/ra_ide_api/src/lib.rs b/crates/ra_ide_api/src/lib.rs
index d25795adc..d4be8bd6c 100644
--- a/crates/ra_ide_api/src/lib.rs
+++ b/crates/ra_ide_api/src/lib.rs
@@ -19,6 +19,7 @@ mod status;
 mod completion;
 mod runnables;
 mod goto_definition;
+mod goto_type_definition;
 mod extend_selection;
 mod hover;
 mod call_info;
@@ -416,6 +417,13 @@ impl Analysis {
         self.with_db(|db| impls::goto_implementation(db, position))
     }
 
+    pub fn goto_type_definition(
+        &self,
+        position: FilePosition,
+    ) -> Cancelable<Option<RangeInfo<Vec<NavigationTarget>>>> {
+        self.with_db(|db| goto_type_definition::goto_type_definition(db, position))
+    }
+
     /// Finds all usages of the reference at point.
     pub fn find_all_refs(
         &self,
diff --git a/crates/ra_lsp_server/src/caps.rs b/crates/ra_lsp_server/src/caps.rs
index f6d2b75e7..9095bee89 100644
--- a/crates/ra_lsp_server/src/caps.rs
+++ b/crates/ra_lsp_server/src/caps.rs
@@ -2,7 +2,7 @@ use lsp_types::{
     CodeActionProviderCapability, CodeLensOptions, CompletionOptions, DocumentOnTypeFormattingOptions,
     ExecuteCommandOptions, FoldingRangeProviderCapability, RenameOptions, RenameProviderCapability,
     ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability, TextDocumentSyncKind,
-    TextDocumentSyncOptions, ImplementationProviderCapability, GenericCapability,
+    TextDocumentSyncOptions, ImplementationProviderCapability, GenericCapability, TypeDefinitionProviderCapability
 };
 
 pub fn server_capabilities() -> ServerCapabilities {
@@ -23,7 +23,7 @@ pub fn server_capabilities() -> ServerCapabilities {
             trigger_characters: Some(vec!["(".to_string(), ",".to_string(), ")".to_string()]),
         }),
         definition_provider: Some(true),
-        type_definition_provider: None,
+        type_definition_provider: Some(TypeDefinitionProviderCapability::Simple(true)),
         implementation_provider: Some(ImplementationProviderCapability::Simple(true)),
         references_provider: Some(true),
         document_highlight_provider: Some(true),
diff --git a/crates/ra_lsp_server/src/main_loop.rs b/crates/ra_lsp_server/src/main_loop.rs
index dc1f8f3f7..87b4e3ac2 100644
--- a/crates/ra_lsp_server/src/main_loop.rs
+++ b/crates/ra_lsp_server/src/main_loop.rs
@@ -306,6 +306,7 @@ fn on_request(
         .on::<req::WorkspaceSymbol>(handlers::handle_workspace_symbol)?
         .on::<req::GotoDefinition>(handlers::handle_goto_definition)?
         .on::<req::GotoImplementation>(handlers::handle_goto_implementation)?
+        .on::<req::GotoTypeDefinition>(handlers::handle_goto_type_definition)?
         .on::<req::ParentModule>(handlers::handle_parent_module)?
         .on::<req::Runnables>(handlers::handle_runnables)?
         .on::<req::DecorationsRequest>(handlers::handle_decorations)?
diff --git a/crates/ra_lsp_server/src/main_loop/handlers.rs b/crates/ra_lsp_server/src/main_loop/handlers.rs
index 530081494..23802e5e1 100644
--- a/crates/ra_lsp_server/src/main_loop/handlers.rs
+++ b/crates/ra_lsp_server/src/main_loop/handlers.rs
@@ -288,6 +288,26 @@ pub fn handle_goto_implementation(
     Ok(Some(req::GotoDefinitionResponse::Link(res)))
 }
 
+pub fn handle_goto_type_definition(
+    world: ServerWorld,
+    params: req::TextDocumentPositionParams,
+) -> Result<Option<req::GotoTypeDefinitionResponse>> {
+    let position = params.try_conv_with(&world)?;
+    let line_index = world.analysis().file_line_index(position.file_id);
+    let nav_info = match world.analysis().goto_type_definition(position)? {
+        None => return Ok(None),
+        Some(it) => it,
+    };
+    let nav_range = nav_info.range;
+    let res = nav_info
+        .info
+        .into_iter()
+        .map(|nav| RangeInfo::new(nav_range, nav))
+        .map(|nav| to_location_link(&nav, &world, &line_index))
+        .collect::<Result<Vec<_>>>()?;
+    Ok(Some(req::GotoDefinitionResponse::Link(res)))
+}
+
 pub fn handle_parent_module(
     world: ServerWorld,
     params: req::TextDocumentPositionParams,
diff --git a/docs/dev/lsp-features.md b/docs/dev/lsp-features.md
index 57015293c..28bae59bb 100644
--- a/docs/dev/lsp-features.md
+++ b/docs/dev/lsp-features.md
@@ -46,7 +46,7 @@ This list documents LSP features, supported by rust-analyzer.
  - trigger characters: `(`,  `,`,  `)`
 - [ ] [textDocument/declaration](https://microsoft.github.io/language-server-protocol/specification#textDocument_declaration)
 - [x] [textDocument/definition](https://microsoft.github.io/language-server-protocol/specification#textDocument_definition)
-- [ ] [textDocument/typeDefinition](https://microsoft.github.io/language-server-protocol/specification#textDocument_typeDefinition)
+- [x] [textDocument/typeDefinition](https://microsoft.github.io/language-server-protocol/specification#textDocument_typeDefinition)
 - [x] [textDocument/implementation](https://microsoft.github.io/language-server-protocol/specification#textDocument_implementation)
 - [x] [textDocument/references](https://microsoft.github.io/language-server-protocol/specification#textDocument_references)
 - [x] [textDocument/documentHighlight](https://microsoft.github.io/language-server-protocol/specification#textDocument_documentHighlight)
diff --git a/docs/user/features.md b/docs/user/features.md
index b44a3fce1..cbfc491b2 100644
--- a/docs/user/features.md
+++ b/docs/user/features.md
@@ -42,6 +42,18 @@ is a relatively new feature of LSP:
 https://github.com/Microsoft/language-server-protocol/issues/613, check your
 editor's LSP library to see if this feature is supported.
 
+### Go to Definition
+
+Navigates to the definition of an identifier.
+
+### Go to Implementation
+
+Navigates to the impl block of structs, enums or traits. Also implemented as a code lens.
+
+### Go to Type Defintion
+
+Navigates to the type of an identifier.
+
 ### Commands <kbd>ctrl+shift+p</kbd>
 
 #### Run